It checks the modules in your node_moudles directory and reports on their status,
specifically if they are linked (e.g. npm linked) or installed (e.g. npm installed)
and if they are staged to be committed by git (e.g. git added).

The problem lmc really solves is when you are:

npm linking your modules during development; and

git committing your node_moudles directory; and

bored of needing to switch to and from linked vs installed modules each time you git commit.

Splitting your node.js project into modules is a good thing. npm linking modules during
development can really save you time. git committing your node_modules is also a good thing
as Mikeal Rogers neatly summaries.

However if you accidentally git commit your node modules while they are npm linked your
source code won't be in a great state. The symlinks created by npm link are unlikely to work
on any machine other than your own so when you git clone/pull/push your project somewhere else
it is unlikely to run without some manual npm tinkering first. Even worse, unless you have done
some diligent publishing of your module elsewhere it may not be possible to get hold of the right
version to make your project run at all.